Caption: Quantum waves. Computer model showing many wave paths superimposed onto the surface of a sphere. The paths simulate the motion of a particle which is behaving like a wave (wave-particle duality). Quantum theory states that as the particle moves it creates many "wave trains", which can collide to produce one random quantum wave, an example of quantum chaos. Chaos in classical mechanics would result in waves travelling in all possible directions randomly, whereas in quantum mechanics, chaos is approached when the waves are added together randomly. The waves were modelled by Professor Eric Heller, Harvard University, USA.